Quite often you will find dogs/pups in rescue for one or the other of the mixed breeds. If you check either Yorkie or Maltese rescues (hope I got the mix right), you might just find your pup through rescue.
When searching for my purebreds, both Lab & Pyr, I researched and found the right breeder. The majority of the 4 legged kids I've had through my life were mixed breed rescues.
"Some days you're the dog; some days you're the hydrant". author unknown